Means for indicating braking action



July 26, 1938..

.R. W. WARING ET AL MEANS FOR INDICATING BRfXKING ACTION Original Filed Dec. 14, 192a 2 Sheets-Shet 1 /izJwzzozs 7M??? lawn @mammzg 5/5 July 26,1938; R. w. WARING ET AL 3 MEANS FOR INDICATING BRAKING ACTION OrigiHal'Filed D96. 14, 1928 2 Sheets-sheet 2 i atenteci July 2, l38 v artiste MEANS FOR mnron'rrao enhance horrors Robert W. Waring and Richard J. Fallacy, Evans ton, 11L; said Waring assignor to said li ahey Implication December lid, lbw, Serial lilo. thb ildh Renewed December b ll, will '7 Claims.

The present invention relates to a new and improved means for indicating braking action, and although adaptable to a large variety of brakes, it is particularly applicable to automobile brakes.

An important object of the present invention resides in the provision of novel means which will indicate the action and effectiveness of a brake by measuring the braking torque.

Another object is to provide a novel means of this character which will register the action of the brake at a point remote therefrom, for example at the dash of an automobile.

In most motor vehicles, for example in automobiles, a plurality of brakes, usually two or four, are provided; The action of these brakes should be balanced. Ordinarily it is dimcult todeterrnine when the brakes are out of balance, and to set and test the brakes so as to bring them into accurately balanced relation. An important object of the present invention therefore resides in the provision of a novel braking system comprising means for indicating therelative braking action of a plurality of brakes. As a result, the working condition of the brakes is revealed whenever the brakes are operated, and the brakes can be set and tested accurately and expeditiously.

Another important object is to provide a novel means for testing brakes which will indicate the efficiency of any one or more of the brakes by comparison of the braking action to the power applied to the brake.

Most of the brakesin common use comprise a brake drum, an internal or external brake member, and means for manipulating the latter into or out of engagement with the drum. A specific object of the present invention resides in the provision of novel means for registering the torque exerted through friction by the brake drum on the brake member when the brake is applied.

A further object resides in the provision of novel means of the foregoing character which is relatively simple and inexpensive in oonstruction, and which is eillcient and accurate in operation.

Further objects and advantages will become apparent as the description proceeds.

In the accompanying drawings, Figure 1 is a. plan view, diagrammatic in character, of a braking system embodying the features of our invention.

Fig. 2 is an enlarged sectional detail view of one of the brakes, taken along line 2-2 of Fig. 3.

Fig. 3 is an axial sectional view through one of the brakes and the wheel to which it is' applied.

Fla. l is a front elevational view of a' suitable indicating device.

Fig. 5 is a sectional view taken along line til-b 5 oi Fla. i.

Fig. c is a transverse sectional view taken along line @-ii of Fig. 5.

While the invention is susceptible of various modifications and alternative constructions, we have shown in the drawings and will herein describe in detail the preferred embodiment, but it is to be understood that we do not thereby intend to limit the invention to the specific form disclosed, but intend to cover all modifications and alternative constructions falling within the spirit and scope of the invention as expressed in I the appended claims.

The invention in its broadest concept is applicable to a large variety of brakes, but for purposes of illustration is described in connection with a hydraulic brake comprising a rotatable brake drum ill adapted to be mounted on a wheel ii concentric to the axis of rotation. Disposed within the brake drum it are two arcuate peripherally eirpansible brake shoes 02 pivotally connected by a pin it. Suitable means is provided for applyingthe brake shoes $22 to the drum ill. and in the present instance, this means comprises a cylinder it connected through a line i i to a suitable source of pressure fluid (not shown). The cylinder is "is mounted between the free ends of the shoes ill on a plate lb disposed in the open end-oi the dram ill and. secured against rotation relative to the axle it of the wheel ll. Slldably disposed in opposite ends. of the cylinder iii are two opposed pistons ll operatively connected respectively to the free ends of the brake shoes ii. In the present instance, the free ends oi the brake shoes i2 are Iormed with reduced extensions is. rounded at their ends, and engaging in rewsses it in the outer ends of the pistons ll. It will be evident that when pressure fluid is admitted to the cylinder i3, the pistons ll will expand the brake shoes it into peripheral and frictional engagement with the brake drum. ill. A suitable coil spring 2b is anchored at its ends to the free ends of the shoes i2, and serves to contract the latter when the brake is released. 50 When the brake is applied, the brake drum It will apply a rotational torque to the brake shoes i2. one of the important features of the present invention resides in determining the braking 1 this torque. To this end, 5

of the shaft directly 'journaled thereon. The

the pivot pin 2! for the shoes I! is disposed in a slot 22 in the free end of a lever 23 pivotally anchored on a pin 24 on the mounting plate l5. Formed integral with the lever 23 is a clevised arm 25, the free end of which projects into coactin relation with a yieldable abutment 28 Movement 'of the arm '25 is limited by suitable spaced stop lugs 26a and 26b projecting at opposite sides thereof from the mounting plate It.

iting stop in the event of excessive braking or when the yieldable abutment 26 is ineflective.

Preferably, the abutment 525 is a compression unit, such as a sealed corrugated bellows, one end of which is fixed to the mounting plate i5, and the other end of which is movable and in contact with the free end of the arm 25. The unit 26 is adapted to be filled with a suitable fluid, such as oil or water, and is connected through a pressure line 271 to a suitable indicating device it. Interposed in the line 21' is an adjustable member or wall 29 for adjusting the reading of the device 28. It will be evident that the abutment it constitutes a movement detecting device for the brake shoes l2, and that its displacement is proportional to the braking torque. The arm 25 by reason of its length relative to the arm 23 substantially reduces the pressure on the abutment 2d and increases its proportional movement. I

In the present embodiment of the invention, we have shown four brakes applied respectively to the four wheels ll of an automobile. Hence, four lines 2? are connected to the indicating device 28..

While the indicating device 28 may be of any suitable type or form, in the present instance it comprises an outer casing to adapted to be mounted on the dash st of the automobile. Preferably the casing ad is cylindrical in shape, and is closed at its rear end with an integral wall 32. The front end of the casing at is closed by a suit able cover glass 33 removably secured in place by a suitable flange ring dd Any suitable means responsive to the pressure in the unit 26 may be provided, and in the present instance a plurality of Bourdon tubes 35 to 353' are mounted in the casing 3d. Preferably, the Bourdon tubes are mounted in alignment axially of the casing 3d, and the fixed ends thereof are secured to a supporting block it extending along the bottom of the casing. The block it is formed with a plurality of passages if! to 455 communicating with the fixed ends of the tubes 35 to 39. Four of these passages dl to M communicate respectively with the four lines El; and the fifth passage 45 communicates with a line it leading to the source of pressure fluid (not shown) for actuating the brakes.

The free ends of the Bourdon tubes 35 to 39 are connected respectively by suitable linkages t! to SI to a plurality of shafts 52 to 56. Preferably,

' the shafts are arranged concentrically, and .ex

tend axially of the casing til. The inner shaft 52 is journaled at its rear end in the wall 32, and the outer shaft 56 is iournalcd in a dial 51? mounted in the-casing it slightly back of the glass 32.

Secured respectively to the forward ends of the shafts It to 56 are a plurality of indicator needles 58 to 62 which overlie suitable scales 53 to 61 on the dial 51. To facilitate connecting the shafts to the tubes, and mounting the needles on the shafts, each shaft projects beyond the ends scales 63 to 81 may be arranged in any suitable manner on the dial :51, but preferably are coincident radially. To facilitate reading the device 28, the needles 58 to 62 are varied progressively in length, and the foremost needles are bent rearwardly so as to position their points directly over the dial 51.

It will be evident that we have provided a novel means for registering the effectiveness of any one brake and the relative effectiveness of a plurality of brakes. The efllciency of each brake is indicated by comparing its action to the power applied thereto. Readings are made on a single dial, and the relative action of a plurality of brakes is indicated by the relative divergence of the corresponding indicating needles. Low effectiveness of any one or more brakes, and/ or an unbalanced braking action can be easily detected, and can be accurately and expeditiously noted and corrected. The needles can be relatively ad- Justed to bring them to a zero reading by adjusting the members 29.

We claim as our invention:

1. A brake comprising, in combination, a brake drum, a brake shoe arranged to engage said drum, 8. fixed support, a yieldable abutment mounted on said support, a lever plvotally mounted on said support, said lever having one arm having a pin and slot connection with said shoe and having a second arm coacting with said yieldable abutment, means connected with said abutment for for indicating the yield thereof.

2. A brake comprising, in combination, a brake drum, a brake shoe arranged to engage said drum, 9. fixed support, a yieldable abutment mounted on said support, a lever pivotally mounted on said support, said lever having one arm having a pin and slot connection with said shoe and having a second arm coacting with said'yieldable abutment, means connected with said abutment for indicating the yield thereof, and positive stop lugs disposed at opposite sides of said second arm tolimit the movement thereof, said second arm being substantially longer than said first mentioned arm.

3. A brake comprising, in combination, a brake drum, a fixed support, a brake shoe having a floating connection with said support, said connection having an arm movable proportionately to movement of said shoe with said drum, means for bringing said shoe into frictional engagement with said drum, a sealed pressure fluid system comprising a presssure responsive member and a compressible abutment, said abutment being mounted on said support and coacting with said arm, and positive stops for limiting the movement of said arm in each direction of movement.

4. A device for indicating the braking action of an automobile brake comprising, in combination, a non-rotative support adjacent the brake, a lever pivotally mounted on said support and movable by the braking member of said brake, mechanism mounted on said support for yieldably resisting the movement of said lever, an indicator mounted on the dash of the automobile, and means connecting said indicator with said mechanism to permit said indicator to show the extent of the resistance offered by said mechanism.

5. A device for indicating the braking action of an automobile brake of the internal expanding type having a pair of shoes pivotally connected to eachother in end-to-end relation, said device comprising, in combination, a lever connected to the pivotal connection of said shoes and mov- I able by the circumterentiaimovement of said shoes, means mountedadiacent said shoes for yieldably resisting the movement of said lever, an indicator mounted on the dash of the automobile tor indicating the resistance oiTered by said means. and a connection between saidmeans and said indicator.

6. A device for indicating the braking action of an automobile brake having a drum, a plate covering the race of said drum, and a pair of shoes enclosed within the drum and adapted to engage frictionaily with said drum, said device comprising, in combination, a lever pivotally mounted on said plate and having one end connected to said shoes, means mounted on said plate within said drum for yieldably resisting movement of said lever, an indicator mounted on the dash of the automobile for indicating the resistance offered by said means, and a flexible connection between said means and said indicator.

7. In combination with the wheel of a, vehicle including a brake drum,"a brake shoe for engaging said drum, a stationary fulcrum, a lever pivotally mounted on the fulcrum and engaged by the shoe, and a pressure responsive device engaging the lever, said device having indicating means to indicate the different degrees of braking torque exerted by the shoe. a

' ROBERT W. WARING.

RICHARD J. FAHEY. 

